gears and ignore both essential geometry and detailed kinematics. Indeed it soon becomes obvious to the inquirer that even those sources having ‘valve gears’ in the book title fail to satisfy, and that educated guesswork leaves the model engineer particularly disadvantaged.
Much frustrating study gradually formed a clearer picture, aided by close correspondence with like-minded devotees – Jim Ewins and Ted Gowan, the former experimentally inclined, admitting of nothing other than strict principle, and the latter retired from the Canadian National Railway and a mine of information and good practice. Alan Gettings lent his mathematical expertise. The culmination was Don Ashton’s production of two booklets dedicated to Walschaerts’ Gear and Stephenson’s Gear, published in 1976. These volumes were combined and updated with additional information in 2000 and again in 2007, when the opportunity to include the advances in computer simulation became so useful.
Don Ashton is neither engineer nor mathematician by profession but has long been active in valve gear design and modification for small scale locomotives, seeking knowledge from the dwindling ranks of those professionally involved, and enthusiastically corresponding with those whose primary object was and is to demystify the subject. Regrettably, the few professionals intimately concerned with the details of valve gear design appear not to have considered publication of their skills and knowledge worthwhile. Many must be the discarded personal note books and scraps of calculations that would enlighten, if found.
This web site is intended to aid those interested in pursuit of clarity and is not of itself finite.
Outside the locomotive and model engineering fields Don Ashton has held a long standing interest in tugs and their operations and has written extensively on the subject for a professional specialist magazine. In fact his authorship extends to other interests: as a qualified teacher and a well respected repairer of woodwind instruments he is active as a writer, arranger and adult residential course tutor. A long time champion of the saxophone, he is responsible for a specialist chapter in the CUP’s ‘Cambridge Companion to the Saxophone’.